Life in harsh environments: carabid and spider trait types and functional diversity on a debris‐covered glacier and along its foreland

Abstract

1. Patterns of species richness and species assemblage composition of ground‐dwelling arthropods in primary successions along glacier forelands are traditionally described using a taxonomic approach. On the other hand, the functional trait approach could ensure a better characterisation of their colonisation strategies in these types of habitat. 2. The functional trait approach was applied to investigate patterns of functional diversity and life‐history traits of ground beetles and spiders on an alpine debris‐covered glacier and along its forefield in order to describe their colonisation strategies. 3. Ground beetles and spiders were sampled at different successional stages, representing five stages of deglaciation. 4. The results show that the studied glacier hosts ground beetle and spider assemblages that are mainly characterised by the following traits: walking colonisers, ground hunters and small‐sized species. These traits are typical of species living in cold, wet, and gravelly habitats. The diversity of functional traits in spiders increased along the succession, and in both carabids and spiders, life‐history traits follow the ‘addition and persistence model’. Accordingly, there is no turnover but there is an addition of new traits and a variation in their proportion within each species assemblage along the succession. The distribution of ground beetles and spiders along the glacier foreland and on the glacier seems to be driven by dispersal ability and foraging strategy. 5. The proposed functional approach improves knowledge of the adaptive strategies of ground‐dwelling arthropods colonising glacier surfaces and recently deglaciated terrains, which represent landforms quickly changing due to global warming.

Assemblage Characteristics and Habitat Specificity of Carabid Beetles in a Japanese Alpine-Subalpine Zone

“…In the Italian Alps, the species richness, activity level, and species traits (i.e., wing forms, geographical ranges, diets, and reproduction rhythms) of carabid beetles showed no or only weak correlation with altitude but were closely associated with habitat type [11]. Although there have been numerous studies on the habitat associations of carabid beetles in high-altitude mountain areas in Europe [12][13][14], such associations have not been reported from above the tree line in Japanese mountains.…”

Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

“…Sampling was performed during the snowfree period, between late June and late September, in 2011-2012 for carabids and in 2014 for chironomids. Annual mean below-ground temperature on the glacier foreland, recorded during the period 5 August 2011 to 5 August 2012, was 1.7°C, while mean below-ground relative air humidity was 96% (Gobbi et al, 2017). On the glacier foreland (mean elevation 2520 m asl) plant cover ranged from 5% to 70%, dominated by Poa alpina, Poa laxa, Saxifraga bryoides, Geum reptans, and Luzula alpinopilosa.…”

“…AD 1850). Field observations and various sources, including maps, reports, aerial photographs, iconography, and records of length change collected over the last 100 years, allowed us to reconstruct the glacier tongue position during the LIA, in 1925, 1994, 2003(Gobbi et al, 2017 and 2013 (Casarotto and Bertoni, 2015) (Fig. 1).…”

“…On the glacier foreland (mean elevation 2520 m asl) plant cover ranged from 5% to 70%, dominated by Poa alpina, Poa laxa, Saxifraga bryoides, Geum reptans, and Luzula alpinopilosa. Outside the glacier foreland (mean elevation 2426 m asl), Late Glacial sites are occupied by Carex curvuladominated communities with >80% ground cover (Gobbi et al, 2017). Time since deglaciation, thus the distance from the glacier front, was the main variable influencing positively plant species richness, vegetation cover, and soil organic matter (Gobbi et al, 2017).…”

“…We selected the Vedretta d'Amola glacier foreland in Italian Alps which has been investigated previously from the glaciological, geomophological and ecological point of view (Losapio et al, 2015;Losapio et al, 2016;Tenan et al, 2016;Gobbi et al, 2017;Lencioni, 2018). The general aim was to investigate if global warming affects in the same way terrestrial and aquatic glacial communities trophically related, and to know which species and in which relative proportion colonize aquatic and terrestrial habitats left free under glacier retreating, so describing primary succession patterns.…”